The conclusion discusses the reasons for the rising use of the autism diagnosis, proposing there may be an interaction in which increased risk posed by changing social, medical and environmental practices has increased the number of people with milder neurodevelopmental differences at the same time as they become ‘diagnosable’; that is, as the boundaries of the category have shifted. Reflecting on our attempts to study autism has highlighted how difficult it is to locate, so instead of asking ‘What is autism?’, some consideration is given to the question of ‘Where is autism?’ The book concludes with my own thoughts on my diagnostic status in relation to autism and neurodiversity, plus some hopes for the future.